Rotary pump



Jan. 3, 1928.

R. J. P. E. COZETTE ROTARY PUMP Filed Deo. 12. 1925 3 Sheets-Sheet l x Y m A M m f r l -xn?" l .5f Lw/MM @7 @M Jan. 3, 19728.

* R. J. P. E. COZETTE ROTARY PUMP Filed Deo. 12, 1925 3 Sheets-Sheet 2 Jan. 3, 1928. 1,654,864

R. J. P. E. COZETTE ROTARY PUMP Filed Dec. 12, 1925 3 Sheets-Sheet 5 WW ,@/m/ a@ 55 open Patented Jan. 3, :1928. v

UNITED STATES REN JEAN PAUL EMILE, cozn'rrn,

F NEUILLY-SUBSEINE, FRANCE.

ROTARY PUMP.

Application lcd December 12, 1925, Serial No. 75,089, and in France January `31, 1925.

This invention relates to improvements in rotary vacuum or pressure pumpshaving a rotor provided with blades and adapted to work at high speed, and has for its object to interpose between the rotor and stator a l hollow cylindrical drum or casing turning with the rotor at the same angular velocity as the latter, against which the ends of the blades abut or bear, so that the frictional H) etfocts of the blade relative to the to centrifugal force, are nullified. l Another object of the invention is to provide novel means for accomplishing the synchronous movement of the rotor and casing above referred to.

ln the drawings Fig. l is a diagrammatic section in a plane perpendicular to the axis of rotation, of a pump offusual construction of that type t0 which the present invention is particularly applicable.

Fig. 2 is a diagram illustrating the principle of the present invention.

Fig. 3 is a cross section similar to that of Figure l, through a pump to which the present invention has been applied, taken a ong line 3-3 of Fig. 4. y

Fig. 4 is a diametrical section of the same in a plane passing through the axis, taken along the line 4-4 of Fig. 3.

Fig. 5 is a cross section taken along the line 5-5 of Fig. 4.

It is known that pumps of this type are formed in a general way (as shown 1n the diagrammatic: Figure l) by a cylindrical body of stator S in the interior of which turns a cylindrical drum or rotor. R. The axis of the rotor is parallel to that of the body S but it is set eccentrically relatively to the said axis by an amount L in such a way that the rotor makes contact with the inner surface of the stator at the point A.

Blades P are located in grooves r formed in the rotor.

An apparatus thus constructed operates in the following manner: i

If it is assumed that the rotor turns in the direction lof the arrow f, it will be noted that commencing from the point of contact A the volume comprised between two adjacent blades increases constantly through 180. This volume reaches a maximum when the chamber under consideration arrives at B.v The chambers which are thus to suction communicate with the general admission duct C. On the other hand casing due value of the above pressuret during the 'second half revolution the volume of the chambers decreases rapidly until it reaches a minimum again at the point of contact' A. The fluid is thus delivered through the duct D.

ln such an apparatus the blades are dis placed towards the periphery and pressed against the inner surface of the stator by the action of the centrifugal force produced by the rotation of the rotor.

Pieces of apparatus of this type possess a simplicity of construction which makes them very attractive but they possess the following essential disadvantage: the blades being displaced from the centre towards the periphery by the action of centrifugal force, in proportion as the speed of rotation increases, the pressure due to this centrifugal force in- Snce the variations in pressure are uare of the speed, the pressure rapidly reac es a very rhigh value. As a result a great amount of friction is produced between the outer edges of the plates and the inner surface of the stator, which friction is detrimental to the obtaining of a good mechanical eiiiciency of the apparatus. As a result also of this increase in pressure, lubrication diiiculties arise beyond a certain speed; for a redetermined e lubricating oil is even completely expelled and the blades become ra idly destroyed.V

It has already een proposed, in order to overcome the above mentioned disadvantage, to interpose between the rotor and the stator a holle/w cylindrical drum or casing turning with the rotor at the same angular velocity as the latter; the object of this arrangement is to nullify the effect of the centrifugal force by virtue of the fact that when the apparatus is working the blades do not bear against a fixed surface. "i

In fact in a pump comprising this movement, the blades only move in a. circumferential direction by an amount equal to the eccentricity of the rotor relatively to the stator. The result is that the friction of the outer edge of the blades is almost completely prevented, the effect of which is to completely remove the diiculties of lubrication and the loss in mechanical eticiency.

In order for such a device to preserve its elciency the rotor and the casing must rotate with the same angular velocity. As the rotor and the casing turn in the same direction the blades tend to carry the said casing proportional to the s mounted upon two bal along in the same direction and at the saine speed. This form of drive in which the casing is driven by the blades could be considered to be suiicient. However, it is subject to certain defects such as untimely relative displacement of' the two members in question so that it is preferableto provide a suitable mechanical connection between them. It has already been suggested to provide means for obtaining such a connection by means of an arrangement of gears.

The present invention relates to a particularly simple device for producing the said connection.

This device is based principle (see Fig. 2) y Consider a circle E turning about the centre O and a circle e turning about the centre o, the distance between the centres O and o being such that the two circles make internal contact at a point Fon the anis X-X1 passing through the centres O and o; it is easy to show that if the two circles turn with the same angular velocity each point on the inner circle e describes a circle e making contact internally at F with the circumferences of the circles E4 and e the radius of which circle e is equa-l to the amount a of eccentricity of the centres of the circles E and e relatively to each other.

It follows that in order to drive the rotor and the casing at the same angular velocity it is suiiicient to provide driving arms integrally attached to the rotor and moving in circular cavities formed in one of the ends of the casing.

Figs. 3, 4 and 5 upon the following illustrate diagrammatically and by way of example alone a form of construction of this device.

s shown in these figures, the rotor 1 is enclosed, in conformity to the arrangement described above, in a cylindrical Adrum 2 earin s 3 and 3. The blades 4 are guided in radigal grooves 5 formedfin the rotor. The casing 2 is closed by an end piece 6 in the wall of which are formed a number of circular cavities 7 arranged in the form of a crown concentrically about the axis of the said casing.

In the form of construction shown by way of example, six cavities are provided (Fig. 5) spaced 60 apart. Further, upon the shaft 8, 8 of the rotor is keyed a late 9 provided with as many rotating rol ers 10 as the end piece 6 comprises circular cavities (six in the example described); the rollers l0 are spaced apart at regular intervals about the centre of the plate f The circle which passes through the centres of the circular cavities 7 formed in the end piece 6 ot the casing 2 has the saine diameter as the circle which passes through the centres of the rollers l0 so that the said y rotor.

Itectly regular and rollers are always in contact with the edges of the circular cavities. Further, the radius of the said cavities is equal to the sum of the amount of eccentricity a plus the radius of the rollers.

Figure 5 shows that the rollers 10 make good contact with the circumference of the cavity 7; it is obvious that this is true whatever be the angular displacement of the As a. result the casing is driven by the rotor by means ot' this device in a persilent manner on ac# count ot' the tact that all gears are dispensed with and this drive gives rise to a very small loss of eiiiciency. Moreover, this driving device may be very easily lubricated with absolute efficiency.

lVhat I claim is:A

l. A vacuum or blades and rotating on an axis eccentric to the axis of said stator 'at a high speed, com p'rising a stator, a rotor, said rotor being adapted to turn within said stator, a cylindrical 'drum placed between-the blades and said rotoi. said drum being adapted to nullify the objectional eliects lof the centrifugal force produced, an end plate integrally attached to said drum, circular cavities formed in said plate, said cavities being arranged in the form of a crown and spaced at regular intervals apart upon said end plate, a plate integrally attachied to the shaft of said rotor, rollers carried upon'said plate, said rollers corresponding in number to said cavities and being arranged to remain in contact with 'the circumference of the corresponding cavities for all positions of said rotor,said cavities having a radius equal to the eccentricity of said rotor plus the radius of said rollers, said 'drum being driven by this means at the same angular velocity as said rotor.

' 2. A driving device comprising a driving plate und a driven plate said driven plate having its axis of rotation placed eccentrically relatively to the axis of rotation ot' a said y suitable dimensions formed in said driven plate, said cavities being arranged in the form ot a crown and spaced at` equal intervals apart upon said driven plate, rollers carried upon said driving plate, said rollers corrcspondine1 in number to said cavities the centers oi said cavities and the axes of said rollersbeing arranged in circles oi' eipial'diameters so that the rollers are adapte( to make contact with the circumference of said cavities for all positions of saidl driving plate, the rotation of said driving plate producing the rotation of said driven plate at the saine angular velocity as said driving plate.

in testimony whereof l' name to this specitication.

JEAN FAU?. Eiilllt CZETTE.

have signed my pressure pump having driving plate, circular cavities ot`` iuo 

